The 550 shares many of the features of PIAA&#8217;s 525 but in a much larger package approximately 8 vs. 6 inches in diameter. Like the 525 Series the 550 features PIAA&#8217;s new high impact, weather resistant connectors. The 550 utilizes a yellow top H4 bulb when combined with a Super White Wedge bulb (located within the lamp) and an Plasma Ion lens, creates a soft amber glow that is simply stellar.